The following nodes, interfaces and links are defined following introduction of a relay node to a Long Term Evolution-Advanced (LTE-A) system as illustrated in FIG. 1.
Nodes include:
Donor-eNB: an eNB (evolved base station) in radio connection with an Relay Node (RN) device or simply DeNB;
Relay-Node: an entity between the DeNB and a UE or simply an RN device;
Relay-UE: a UE in data interaction with the RN device or simply R-UE; and
Macro-UE: UE directly in data interaction with DeNB.
Interfaces include:
Un interface: an interface between the RN device and the DeNB; and
Uu interface: an interface between the UE and the RN device.
Radio links include:
Backhaul link: a link corresponding to the Un interface;
Access link: a link corresponding to the Uu interface; and
Direct link: a link over which data is transmitted between the DeNB and the macro UE.
Downlink transmission following introduction of the RN device: data of the UE arriving at the RN device has to be transmitted from the DeNB to the RN device over a downlink backhaul link and then transmitted from the RN device to the UE over a downlink access link.
Uplink transmission following introduction of the RN device: uplink transmission of the UE under the RN device is firstly transmitted from the UE to the RN device over an uplink access link and then transmitted from the RN device to the DeNB over a backhaul link.
In an LTE system at present, feedback information (Acknowledgement/Negative Acknowledgement, ACK/NACK) corresponding to downlink data received at a user equipment over a Physical Downlink Shared Channel (PDSCH) is transmitted over a Physical Uplink Control Channel (PUCCH) resource allocated at the network side, and the PUCCH resource is bound with an index of a Control Channel Element (CCE) over a Physical Downlink Control Channel (PDCCH). However, there is no solution to allocation of a PUCCH resource to a relay node device in an LTE-A system, thus making it rather difficult for the relay node device to return uplink feedback information over a PUCCH resource upon reception of downlink data from a base station.
In summary there is no solution to allocation of a PUCCH resource to a relay node device in the existing LTE-A system, thus making it rather difficult for the relay node device to transmit uplink feedback information over a PUCCH resource upon reception of information from a base station.